<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    /* 默认样式 */
		body {
			margin: 0;
			padding: 0;
			font-family: Arial, sans-serif;
		}
		header {
			background-color: #333;
			color: #fff;
			padding: 20px;
			text-align: center;
		}
		nav {
			background-color: #f2f2f2;
			padding: 10px;
			text-align: center;
		}
		nav ul {
			list-style: none;
			margin: 0;
			padding: 0;
		}
		nav li {
			display: inline-block;
			margin: 0 10px;
		}
		nav a {
			color: #333;
			text-decoration: none;
			padding: 5px 10px;
			border: 1px solid #333;
			border-radius: 5px;
		}
		section {
			padding: 20px;
			text-align: center;
		}
		footer {
			background-color: #333;
			color: #fff;
			padding: 20px;
			text-align: center;
		}

		/* 响应式样式 */
		@media (max-width: 768px) {
			nav li {
				display: block;
				margin: 10px 0;
			}
		}
</style>
<body>
    <h1>响应式布局示例</h1>
</header>
<nav>
    <ul>
        <li>首页</li>
        <li>产品</li>
        <li>服务</li>
        <li>关于我们</li>
        <li>联系我们</li>
    </ul>
</nav>
<section>
    <h2>欢迎来到我们的网站！</h2>
    <p>这是一个简单的响应式布局示例，当浏览器宽度小于等于768像素时，导航菜单将变为垂直排列。</p >
</section>
<footer>
    <p>版权所有 &copy; 2021</p >
</footer>
</body>
</html>